Pyrithione biocides enhanced by silver, copper, or zinc ions

ABSTRACT

The present invention is directed to an antimicrobial composition, comprising pyrithione or a pyrithione complex; and a zinc or copper or silver source selected from the group consisting of zinc or copper or silver salts, oxides, hydroxides, sulfates, chlorides, metals, and combinations thereof; wherein the weight ratio of the zinc or copper or silver source to the pyrithione or the pyrithione complex is in the range from about 1:300 to about 50:1, and wherein the antimicrobial composition has an enhanced biocidal effect against a variety of free-living microorganisms or biofilms. Also disclosed is a method of inhibiting the growth of free-living microorganisms or biofilm utilizing the above antimicrobial composition, as well as use of such antimicrobial compositions in various products including fuels, fluids, lubricants, coatings, adhesives, sealants, elastomers, soaps, cosmetics, plastic or woven or non-woven fibers, pharmaceuticals, and as preservatives for the above products.

This application is a continuation of U.S. application Ser. No.12/288,557, filed Oct. 21, 2008, which is a division of U.S. applicationSer. No. 09/599,371, filed Jun. 22, 2000, now U.S. Pat. No. 7,455,851,which claims the benefit of Provisional Application Ser. No. 60/141,195filed Jun. 25, 1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to pyrithione biocides, and moreparticularly to a biocidal composition displaying an enhanced biocidaleffect, comprising an antimicrobially effective combination ofpyrithione, pyrithione salt, or pyrithione adduct, and metal ion such asa zinc or copper or silver source such as copper and/or zinc and/orsilver metal, oxide, hydroxide, or salt thereof.

2. Brief Description of the Related Art

Polyvalent metal salts of pyrithione (also known as1-hydroxy-2-pyridinethione; 2-pyridinethiol-1-oxide; 2-pyridinethione;2-mercaptopyridine-N-oxide; pyridinethione; and pyridinethione-N-oxide)are known to be effective biocidal agents, and are widely used asfungicides and bacteriocides in paints and metalworking fluids.Pyrithiones are also used as fungicides and bacteriocides in personalcare products such as anti-dandruff shampoos. The polyvalent metal saltsof pyrithione are only sparingly soluble in water and include magnesiumpyrithione, barium pyrithione, bismuth pyrithione, strontium pyrithione,copper pyrithione, zinc pyrithione, cadmium pyrithione, and zirconiumpyrithione. The most widely used divalent pyrithione salts are zincpyrithione and copper pyrithione.

Zinc and copper pyrithione are useful as antimicrobial agents activeagainst gram-positive and negative bacteria, fungi, and yeasts. Zincpyrithione is used as an antidandruff component in shampoos, whiletechnical suspensions of zinc pyrithione and/or copper pyrithione areused as preservatives in paints and polymers. Synthesis of polyvalentpyrithione salts are described in U.S. Pat. No. 2,809,971 to Berstein etal. Other patents disclosing similar compounds and processes for makingthem include U.S. Pat. Nos. 2,786,847; 3,589,999; 3,590,035; 3,773,770.

While pyrithione biocides have proven useful for a wide range ofapplications as outlined above, the utility of these compounds islimited to the control of select species and strains of fungi andbacteria. Further, while higher concentrations of pyrithione or itssalts have been observed to control the growth of a wider range oforganisms, the useful amount of pyrithione or its salts that can beadded to a commercial product is limited by efficacy and economicconsiderations, and, to a lesser extent, environmental and toxicologicalconcerns.

Copper compounds, such as copper sulfate and cuprous oxide, have beenused widely as fungicides, antifoulants, and algaecides in a large rangeof applications including paints, swimming pool water, and wood productssuch as structural members for buildings or boats. Similarly, inorganicsalts of zinc such as zinc chloride zinc sulfate and zinc oxide, havebeen employed as bacteriostatic and/or fungistatic compounds in a largevariety of products including paints, coatings, and antiseptics.However, while copper salts and zinc salts are less toxic thanpyrithione or its salts, these compounds do not possess the highbiocidal efficacy that is desired in many commercial applications.

Certain combinations of pyrithione and zinc are known in the art.Illustratively, U.S. Pat. Nos. 5,854,266 and 5,883,154 disclose anaqueous antimicrobial composition protected against discolorationattributable to the presence of ferric ion or cupric ion therein,wherein the composition comprises pyrithione and adiscoloration-inhibiting amount (between 0.001% to 10%) of a zinccompound selected from the group consisting of zinc salts of organicacids, zinc salts of inorganic acids, zinc hydroxide, zinc oxide, andcombinations thereof. In another illustration, U.S. Pat. No. 4,161,526discloses a white to cream yellow pyrithione salt or dipyrithione forapplication to skin or hair containing 0.01% to 1% of the zinc salt ofan organic or inorganic acid, zinc hydroxide, zinc oxide, orcombinations thereof. However, this patent does not describe anyadvantageous effect between pyrithione and the zinc salt.

While bacteria and fungi have presented microbial contamination problemsfor many years, biofilms have recently been appreciated as a significantnew source of microbial contamination. Biofilms are generallycharacterized as aggregates of cells adhered to one another or tosurfaces by an extracellular layer of slime. Biofilms are commonly foundas contaminants in metalworking fluids because these fluids contain goodcarbon sources for growth of the organisms that are found in biofilms.However, high concentrations of biofilms in metalworking fluid result inrapid deterioration of the fluid, and can cause equipment problems andfailure.

The growth of biofilms on surfaces can also enhance the rates ofcorrosion of metal surfaces and degradation of paints, surface coatingsand the construction materials underlying these coatings. On ship hulls,the presence of biofilms can lead to increased drag and may encouragecolonization by larger invertebrate biofouling organisms. Biofilms areoften responsible for both internal and cutaneous infections. Theincreased resistance of biofilms to antimicrobial treatments often makebiofilm-related infections more difficult to treat. Medical devices,such as cardiac implants and catheters, and medical instruments, such asdialysis machines and dental waterlines also become contaminated bybiofilms and can spread infection.

While previous efforts have been made to control the growth andproliferation of biofilms, these efforts have met with only limitedsuccess. Research has indicated that biofilm cells are much moreresistant to disinfection than free-living cells, due in large part tothe extracellular slime layer which acts as a protective coating.Moreover, strategies to control microbial contamination heretofore weretypically developed in the laboratory against free-living organisms, andlittle or no attention was given towards determining the effectivenessof antimicrobial agents against biofilm. Unfortunately, the resistantbiofilms are generally not affected by previously employedantimicrobials. If not removed or destroyed, biofilms can cause amultitude of problems in functioning fluid applications, such ascorrosion, clogging, slime build up on surfaces, foul odors, fluidinstability, machine down-time, and the like.

Additional representative patents and publications showing the state ofthe art in the microbial disinfection area are as follows:

U.S. Pat. No. 5,462,589 discloses a composition of made from a coppersalt and sodium pyrithione, and chelates thereof. The mixture is appliedsequentially, fixing the preservative in the wood.

U.S. Pat. No. 4,654,213 discloses an antimicrobial composition in whicha water-soluble salt of zinc enhances the activity of the MgSO₄ adductof 2,2′-dithiopyridine-1,1′-dioxide (MDS).

U.S. Pat. No. 4,370,325 discloses a composition containing2,2′-dithiopyridine-1,1′-dioxide or one of its metal salt adducts,including MgSO₄ (MDS) and Zn salts, for treating eye and ear irritationand inflammation.

U.S. Pat. No. 4,235,873 discloses a deodorant composition containing2,2′-dithiopyridine-1,1′-dioxide or one of its metal salt adducts,including MgSO₄ (MDS) and Zn salts.

British Patent GB 2 230 190 A discloses a preservative compositioncontaining an isothiazolone and the ZnCl₂ adduct of2,2′-dithiopyridine-1,1′-dioxide. However, this patent does not describeany advantageous effect between pyrithione and the zinc salt.

Japanese patent application 6-134227 discloses an antibacterial filterincorporating ZnO or ZnO and zinc pyrithione. However, this patent doesnot describe any advantageous effect between pyrithione and the zincsalt.

Japanese patent application 7-118103 discloses an antimicrobialcomposition for coating stainless steel washing machine drums to preventfouling of inner surfaces wherein ZnO is used as a carrier in a ZPTthermoplastic resin coating. However, this patent does not describe anyadvantageous effect between pyrithione and the zinc salt.

Japanese patent application 06256689 discloses antifungal coatingscomposed of zeolites impregnated with heavy metals, preferably silver,and either a benzimidazole or a metal salt of 2-pyridiylthio-1-oxide,preferably, zinc.

ZnO may enhance the activities of hinokitiol, and certain antibioticsagainst artificial biofilms of S. aureus (Effects of Zinc Oxide on theAttachment of Staphylococcus aureus Strains, H. Akiyama, et al., J.Dermatol. Science 17: 67-74, 1998)

The presence of 0.2% metallic copper or 0.2% metallic zinc was found todecrease the biocidal activity sodium pyrithione in 12 differentmetalworking fluids (E. O. Bennet et al. (1982) Int. BiodeteriorationBull. 18[1]:7-12).

Accordingly, what is needed in the art is biocidal composition thatoffers the biocidal efficacy of pyrithione and its derivatives againstfree-living microorganisms and biofilms, that is highly efficacious andcost-effective, but without environmental and toxicological effects. Thepresent invention is believed to be an answer to that need.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to an antimicrobialcomposition, comprising: pyrithione or a pyrithione complex; and a zincor copper or silver source selected from the group consisting of zinc orcopper or silver salts, zinc or copper or silver oxides, zinc or copperor silver hydroxides, zinc or copper or silver sulfates, zinc or copperor silver chlorides, zinc or copper or silver metals, zinc or copper orsilver complexes, and combinations thereof; wherein the weight ratio ofthe zinc or copper or silver source to the pyrithione or the pyrithionecomplex is in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect againstmicroorganisms selected from the group consisting of free-livingmicroorganisms, parasitic microorganisms, adherent microorganisms,biofilms, and combinations thereof.

In another aspect, the present invention is directed to a method ofinhibiting the growth of microorganisms selected from the groupconsisting of free-living microorganisms, parasitic microorganisms,adherent microorganisms, biofilms, and combinations thereof, comprisingthe step of contacting the microorganisms with an antimicrobialcomposition comprising pyrithione or a pyrithione complex; and a zinc orcopper or silver source selected from the group consisting of zinc orcopper or silver salts, zinc or copper or silver oxides, zinc or copperor silver hydroxides, zinc or copper or silver sulfates, zinc or copperor silver chlorides, zinc or copper or silver metals, zinc or copper orsilver complexes, and combinations thereof; wherein the weight ratio ofthe zinc or copper or silver source to the pyrithione or the pyrithionecomplex is in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect against themicroorganisms.

In yet another aspect, the present invention is directed to a fuel,fluid, or lubricant, comprising water or an organic base fluid and anantimicrobial composition, the antimicrobial composition comprisingpyrithione or a pyrithione complex; and a zinc or copper or silversource selected from the group consisting of zinc or copper or silversalts, zinc or copper or silver oxides, zinc or copper or silverhydroxides, zinc or copper or silver sulfates, zinc or copper or silverchlorides, zinc or copper or silver metals, zinc or copper or silvercomplex, and combinations thereof; wherein the weight ratio of the zincor copper or silver source to the pyrithione or the pyrithione complexis in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect againstmicroorganisms selected from the group consisting of free-livingmicroorganisms, parasitic microorganisms, adherent microorganisms,biofilms, and combinations thereof.

In yet another aspect, the present invention is directed to a coatedsubstrate comprising a substrate together with a coating on thesubstrate, the coating being produced by: (a) contacting the substratewith a coating composition comprising pyrithione or a pyrithionecomplex; and a zinc or copper or silver source selected from the groupconsisting of zinc or copper or silver salts, zinc or copper or silveroxides, zinc or copper or silver hydroxides, zinc or copper or silversulfates, zinc or copper or silver chlorides, zinc or copper or silvermetals, zinc or copper or silver complexes, and combinations thereof;wherein the weight ratio of the zinc or copper or silver source to thepyrithione or the pyrithione complex is in the range from about 1:300 toabout 50:1, and wherein the antimicrobial composition has an enhancedbiocidal effect against microorganisms selected from the groupconsisting of free-living microorganisms, parasitic microorganisms,adherent microorganisms, biofilms, and combinations thereof; and (b)drying the coating composition on the substrate to produce the coatedsubstrate.

In yet another aspect, the present invention is directed to a coatingcomposition, comprising: (a) a base medium comprising water or a solventresin system selected from the group consisting of vinyl, alkyd, epoxy,acrylic, polyurethane and polyester resins, and combinations thereof;and (b) a biocide comprising an antimicrobial composition consistingessentially of pyrithione or a pyrithione complex; and a zinc or copperor silver source selected from the group consisting of zinc or copper orsilver salts, zinc or copper or silver oxides, zinc or copper or silverhydroxides, zinc or copper or silver sulfates, zinc or copper or silverchlorides, zinc or copper or silver metals, zinc or copper or silvercomplexes, and combinations thereof; wherein the weight ratio of thezinc or copper or silver source to the pyrithione or the pyrithionecomplex is in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect againstmicroorganisms selected from the group consisting of free-livingmicroorganisms, parasitic microorganisms, adherent microorganisms,biofilms, and combinations thereof.

In yet another aspect, the present invention is directed to acomposition comprising a plastic or a woven or non-woven fiber, or atextile which comprises, in combination, a plastic or a fiber and anantimicrobial composition consisting essentially of pyrithione or apyrithione complex; and a zinc or copper or silver source selected fromthe group consisting of zinc or copper or silver salts, zinc or copperor silver oxides, zinc or copper or silver hydroxides, zinc or copper orsilver sulfates, zinc or copper or silver chlorides, zinc or copper orsilver metals, zinc or copper or silver complexes, and combinationsthereof; wherein the weight ratio of the zinc or copper or silver sourceto the pyrithione or the pyrithione complex is in the range from about1:300 to about 50:1, and wherein the antimicrobial composition has anenhanced biocidal effect against microorganisms selected from the groupconsisting of free-living microorganisms, parasitic microorganisms,adherent microorganisms, biofilms, and combinations thereof.

In yet another aspect, the present invention is directed to anantimicrobial composition for treating microorganisms selected from thegroup consisting of free-living microorganisms, parasiticmicroorganisms, adherent microorganisms, biofilms, and combinationsthereof, comprising: a salt of pyrithione; and a zinc metal salt;wherein the weight ratio of the water-soluble zinc metal salt to thesalt of pyrithione is in the range from about 1:300 to about 50:1, andwherein the antimicrobial composition has an enhanced biocidal effectagainst free-living microorganisms, parasitic microorganisms, adherentmicroorganisms, biofilms, and combinations thereof.

In yet another aspect, the present invention is directed to an adhesivecomposition, comprising: (a) an adhesive base medium; and (b) a biocidecomprising an antimicrobial composition consisting essentially ofpyrithione or a pyrithione complex; and a zinc or copper or silversource selected from the group consisting of zinc or copper or silversalts, zinc or copper or silver oxides, zinc or copper or silverhydroxides, zinc or copper or silver sulfates, zinc or copper or silverchlorides, zinc or copper or silver metals, zinc or copper or silvercomplexes, and combinations thereof; wherein the weight ratio of thezinc or copper or silver source to the pyrithione or the pyrithionecomplex is in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect againstmicroorganisms selected from the group consisting of free-livingmicroorganisms, parasitic microorganisms, adherent microorganisms,biofilms, and combinations thereof.

In yet another aspect, the present invention is directed to an elastomercomposition, comprising: (a) an elastomeric base medium; and (b) abiocide comprising an antimicrobial composition consisting essentiallyof pyrithione or a pyrithione complex; and a zinc or copper or silversource selected from the group consisting of zinc or copper or silversalts, zinc or copper or silver oxides, zinc or copper or silverhydroxides, zinc or copper or silver sulfates, zinc or copper or silverchlorides, zinc or copper or silver metals, zinc or copper or silvercomplexes, and combinations thereof; wherein the weight ratio of thezinc or copper or silver source to the pyrithione or the pyrithionecomplex is in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect againstmicroorganisms selected from the group consisting of free-livingmicroorganisms, parasitic microorganisms, adherent microorganisms,biofilms, and combinations thereof.

In yet another aspect, the present invention is directed to a sealantcomposition, comprising: (a) a sealant base medium; and (b) a biocidecomprising an antimicrobial composition consisting essentially ofpyrithione or a pyrithione complex; and a zinc or copper or silversource selected from the group consisting of zinc or copper or silversalts, zinc or copper or silver oxides, zinc or copper or silverhydroxides, zinc or copper or silver sulfates, zinc or copper or silverchlorides, zinc or copper or silver metals, zinc or copper or silvercomplexes, and combinations thereof; wherein the weight ratio of thezinc or copper or silver source to the pyrithione or the pyrithionecomplex is in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect againstmicroorganisms selected from the group consisting of free-livingmicroorganisms, parasitic microorganisms, adherent microorganisms,biofilms, and combinations thereof.

In yet another aspect, the present invention is directed to a skin carecomposition, comprising: (a) a skin care base; and (b) a biocidecomprising an antimicrobial composition consisting essentially ofpyrithione or a pyrithione complex; and a zinc or copper or silversource selected from the group consisting of zinc or copper or silversalts, zinc or copper or silver oxides, zinc or copper or silverhydroxides, zinc or copper or silver sulfates, zinc or copper or silverchlorides, zinc or copper or silver metals, zinc or copper or silvercomplexes, and combinations thereof; wherein the weight ratio of thezinc or copper or silver source to the pyrithione or the pyrithionecomplex is in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect againstmicroorganisms selected from the group consisting of free-livingmicroorganisms, parasitic microorganisms, adherent microorganisms,biofilms, and combinations thereof.

In yet another aspect, the present invention is directed to a method ofpreserving cellulose-based material, comprising the steps of: contactinga cellulose-based material with an antimicrobial composition, comprisingpyrithione or a pyrithione complex; and a zinc or copper or silversource selected from the group consisting of zinc or copper or silversalts, zinc or copper or silver oxides, zinc or copper or silverhydroxides, zinc or copper or silver sulfates, zinc or copper or silverchlorides, zinc or copper or silver metals, zinc or copper or silvercomplexes, and combinations thereof; wherein the weight ratio of thezinc or copper or silver source to the pyrithione or the pyrithionecomplex is in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect againstmicroorganisms selected from the group consisting of free-livingmicroorganisms, parasitic microorganisms, adherent microorganisms,biofilms, and combinations thereof.

In yet another aspect, the present invention is directed to a method ofpreserving detergents or surfactants, comprising the steps of:contacting a detergent or surfactant with an antimicrobial composition,comprising: pyrithione or a pyrithione complex; and a zinc or copper orsilver source selected from the group consisting of zinc or copper orsilver salts, zinc or copper or silver oxides, zinc or copper or silverhydroxides, zinc or copper or silver sulfates, zinc or copper or silverchlorides, zinc or copper or silver metals, zinc or copper or silvercomplexes, and combinations thereof; wherein the weight ratio of thezinc or copper or silver source to the pyrithione or the pyrithionecomplex is in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect againstmicroorganisms selected from the group consisting of free-livingmicroorganisms, parasitic microorganisms, adherent microorganisms,biofilms, and combinations thereof.

In yet another aspect, the present invention is directed to apharmaceutical composition, comprising: (a) a pharmaceuticallyacceptable carrier; and (b) an antimicrobial composition, comprisingpyrithione or a pyrithione complex; and a zinc or copper or silversource selected from the group consisting of zinc or copper or silversalts, zinc or copper or silver oxides, zinc or copper or silverhydroxides, zinc or copper or silver sulfates, zinc or copper or silverchlorides, zinc or copper or silver metals, zinc or copper or silvercomplexes, and combinations thereof; wherein the weight ratio of thezinc or copper or silver source to the pyrithione or the pyrithionecomplex is in the range from about 1:300 to about 50:1, and wherein theantimicrobial composition has an enhanced biocidal effect againstmicroorganisms selected from the group consisting of free-livingmicroorganisms, parasitic microorganisms, adherent microorganisms,biofilms, and combinations thereof.

These and other aspects will become apparent upon reading the followingdetailed description of the invention.

BRIEF DESCRIPTION OF THE FIGURES

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a graph showing the antibacterial efficacy of sodiumpyrithione plus Cu(II) or Zn(II) in a metalworking fluid; and

FIG. 2 is another graph showing the antifungal efficacy of sodiumpyrithione plus Cu(II) or Zn(II) in a metalworking fluid.

DETAILED DESCRIPTION OF THE INVENTION

It now has been surprisingly found, in accordance with the presentinvention, that a solution is provided to the problem of providing abiocidal composition that possesses enhanced biocidal efficacy relativeto of pyrithione or its derivatives alone. The present inventors havesolved this problem by developing an antimicrobial compositioncomprising pyrithione or a pyrithione complex in combination with a zincor copper or silver source, for example, a copper salt and/or a zincsalt and/or a silver salt. The composition of the invention displays anenhanced biocidal effect, relative to pyrithione alone, on a wide rangemicroorganisms in both the free-living and biofilm state. Thisantimicrobial performance is greater than might be expected based uponthe additive effect of the individual components of this composition.The enhanced biocidal effectiveness associated with the composition ofthe present invention permits the use of smaller amounts of thepyrithione component of the present composition, as compared to theconventionally employed amounts of pyrithione-based biocides. Thereduction in pyrithione amount, in turn, results in more effectiveelimination of a wide range of free-living microorganisms, parasiticmicroorganisms, adherent microorganisms, biofilms, and combinationsthereof at a lower cost.

As defined herein, the term “enhanced biocidal effect” refers to aninteraction between the pyrithione or pyrithione salt component and themetal ion source of the composition that results in the biocidal effectof the composition being greater than either of the components takenindividually. Thus, the antimicrobial results exceed the expectedbiocidal effect of the combination based upon the performance of theindividual components.

As defined herein, the term “skin care composition” refers to materialsapplied topically to the skin that benefit, improve, or enhance thecondition of the skin, or treat skin suffering from an infectious ordiseased condition. Such skin care compositions include bases such assoap bases, cosmetic bases, medicament bases, cream bases, emollientbases, and combinations thereof, as well as other bases known in theart.

The following discussion elaborates on several particular features ofbiofilms. As defined herein, the term “biofilm” refers to any aggregateof cells anchored to one another, or to surfaces, by extracellularslime. While most unicellular organisms produce a protective coating ofslime, cells aggregated into biofilms are physically different fromfree-living cells and produce much more extracellular slime thanfree-living cells. The slime structures which make up part of thebiofilm are quite complex both biologically and architecturally. Theyare composed of discreet microbial aggregates (microcolonies) separatedby water channels which can form large tower-shaped or mushroom-shapedstructures. As biofilms develop, free-living cell detach from thebiofilm and migrate through the environment in search of new areas thecolonize and form new biofilm. In metalworking fluids, a buildup ofbiofilms can cause many problems, including fluiddeterioration/degradation, foul odors, corrosion, clogging of filters,transfer lines, nozzles, and crevices, fouling of machine surfaces,machine down-time, shorter tool life, fouling and damage of theworkpiece, and the like. As mentioned above, biofilms can also enhancethe rate of degradation of other fluids such as paints or other surfacecoatings. Medical equipment, such as cardiac implants, catheters,dialysis machines, dental waterlines, and the like, may also becomecontaminated by biofilms and spread infection.

Biofilms possess extensive physical and chemical heterogeneity which isnot found in the free-living cells residing in bulk fluid. Becausebiofilm cells are in intimate contact with one another in the biofilm,ecological interaction between the individual organisms can becomecomplex and extensive. Due to the high degree of complexity andheterogeneity that is present in a biofilm, biofilm cells possessdramatically different metabolic parameters as compared to free-livingcells (e.g., metabolic rate, growth rate, preference for specificnutrients, etc.). In addition, cells found in biofilms generally displaya greater diversity of species and organism types as compared tofree-living cells found in bulk fluid.

As indicated above, the present invention is directed to anantimicrobial composition, comprising pyrithione or a pyrithionecomplex; and a zinc or copper or silver source selected from the groupconsisting of zinc or copper or silver salts, zinc or copper or silveroxides, zinc or copper or silver hydroxides, zinc or copper or silversulfates, zinc or copper or silver chlorides, zinc or copper or silvermetals, zinc or copper or silver complexes, and combinations thereof;wherein the weight ratio of the zinc or copper or silver source to thepyrithione or the pyrithione complex is in the range from about 1:300 toabout 50:1, and wherein the antimicrobial composition has an enhancedbiocidal effect against microorganisms selected from the groupconsisting of free-living microorganisms, parasitic microorganisms,adherent microorganisms, biofilms, and combinations thereof. Each ofthese components will be discussed in more detail below.

Pyrithione in its acid form, or a pyrithione complex may be used in thecomposition of the present invention. As defined herein, the term“pyrithione complex” refers to combinations of one or more pyrithionemolecules and one or more metal or ligands, such as pyrithione salts andadducts of pyrithione.

Examples of pyrithione salts that are useful in the present compositioninclude sodium pyrithione, potassium pyrithione, lithium pyrithione,ammonium pyrithione, zinc pyrithione, copper pyrithione, calciumpyrithione, magnesium pyrithione, strontium pyrithione, silverpyrithione, gold pyrithione, manganese pyrithione, and combinationsthereof. Non-metal pyrithione salts such as the ethanolamine salt,chitosan salt, and the disulfide salt of pyrithione (which iscommercially available as OMADINE MDS or OMDS), may also be used. Thetwo most preferred salts of pyrithione useful in the present inventionare the sodium salt (i.e., sodium pyrithione) and zinc pyrithione.Sodium pyrithione is a well-known commercial product that is commonlymade by reacting 2-chloropyridine-N-oxide with NaSH and NaOH, asillustrated in the disclosure of U.S. Pat. No. 3,159,640. Zincpyrithione may be made by reacting 1-hydroxy-2-pyridinethione (i.e.,pyrithione acid) or a soluble salt thereof with a zinc salt (e.g., zincsulfate) to form a zinc pyrithione precipitate, as illustrated in U.S.Pat. No. 2,809,971.

Examples of useful pyrithione adducts include2,2′-dithiopyridine-1,1′-dioxide (also known as omadine disulfide) andalkali or alkaline earth complexes of 2,2′-dithiopyridine-1,1′-dioxide(e.g., the magnesium salt of 2,2′-dithiopyridine-1,1′-dioxide, alsoknown as magnesium pyrithione disulfide or MDS).

Zinc or copper or silver sources useful in the composition of thepresent invention include, for example, raw zinc or copper or silvermetal, zinc or copper or silver salts, zinc or copper or silver oxides,zinc or copper or silver hydroxides, zinc or copper or silver sulfates,zinc or copper or silver chlorides, zinc or copper or silver complexes,and combinations thereof. As defined herein, the term “complexes” refersto an association of a metal ion with a complexing agent (typically anorganic or inorganic ligand). Examples of complexing agents include, butare not limited to, zeolites, titania, carbon, or other inert support,azoles, EDTA (ethylenediaminetetraacetic acid), EGTA(ethylene-bis-(oxyethylenenitrilo)-tetra-acetic acid), crown ethers,cryptates, cyclodextrins, and the like. Zinc or copper or silver sourcesused in the composition of the present invention may also beelectrolytically generated, for example from a silver or copper or zincanode.

Examples of zinc salts that may be used in the composition of thepresent invention include zinc acetate, zinc oxide, zinc carbonate, zinchydroxide, zinc chloride, zinc sulfate, zinc citrate, zinc fluoride,zinc iodide, zinc lactate, zinc oleate, zinc oxalate, zinc phosphate,zinc propionate, zinc salicylate, zinc selenate, zinc silicate, zincstearate, zinc sulfide, zinc tannate, zinc tartrate, zinc valerate, zincgluconate, zinc undecylate, and the like. Combinations of zinc salts mayalso be used in the composition of the invention.

Examples of suitable copper salts include copper disodium citrate,copper triethanolamine, copper carbonate, cuprous ammonium carbonate,cupric hydroxide, copper chloride, cupric chloride, copperethylenediamine complex, copper oxychloride, copper oxychloride sulfate,cuprous oxide, copper thiocyanate, and the like. Combinations of thesecopper salts may also be used in the composition of the invention. Inaddition, combinations of copper salts and zinc salts may also be usedin the composition of the invention.

A variety of forms of silver may also be used in the composition of theinvention. Examples of useful silver species include colloidal silver,silver salts, and silver complexes, such as silver bromide, silverchloride, silver citrate, silver iodide, silver lactate, silver nitrate,silver oxide, silver picrate, and the like.

In addition, other metal ions may be useful in the composition of thepresent invention as a metal ion source. Other useful metal ions includetitanium, cobalt, cadmium, chromium, manganese, platinum, palladium,vanadium, and the like.

Useful amounts of the zinc or copper or silver salts to pyrithione orpyrithione salts range from about 1:300 to about 50:1, and morepreferably from about 1:100 to about 1:10, and more preferably fromabout 1:100 to about 1:1, each ratio expressed on a weight:weight basis.

The composition of the invention can be made by mixing one or moreselected zinc or copper or silver sources and one or more pyrithione orpyrithione complexes in an appropriate media or carrier, or by addingthe individual components separately to the functional blend or fluidbeing treated to impart antimicrobial protection. Useful media orcarriers for the composition include aqueous media such as water, orwater in combination with one or more organic solvent(s). Useful organicsolvents include alcohols, such as methanol, ethanol, alkanolamines,ethers such as glycol ethers, esters, and the like.

The antimicrobial composition of the invention is useful as analgaecide, bactericide, fungicide, insecticide, protozoacide, and/ornematocide, and is particularly useful in inhibiting the growth offree-living microorganisms (including saprophytic microorganisms)parasitic microorganisms (including intracellular, multicellular, andunicellular microorganisms), adherent microorganisms, biofilms, andcombinations thereof. Examples of microorganisms that are effectivelytreated by the composition of the invention include Pseudomonasaeruginosa, Aspergillus niger, Fusarim, Cephalosporium, Pseudomonasfluorescens, Pseudomonas rubescens, Pseudomonas stutzeri, Pseudomonasolevorans, Alcaligenes faecalis, Escherichia coli, Citrobacter freundii,Staphylococcus aureus, Candida albicans, Pityrosporum ovale and thelike. The antimicrobial composition of the invention is a usefuladditive in industrial fluids (e.g., metalworking fluids), paints,coatings, adhesives, sealants, elastomers, personal care products (e.g.,antidandruff shampoos, soaps, skin-care medicaments, cosmetics, and thelike), swimming pool products, wood products, plastic products, medicalproducts, woven or nonwoven fibers (e.g., cotton, wool, silk, linen,leather, and the like), textiles, or any other application wheremicroorganism growth, and particularly biofilm growth, must be stoppedor slowed.

One significant use application for the antimicrobial compositions ofthe present invention is in fuels, fluids, or lubricants, such asmetalworking fluids, cutting fluids, engine fluids, transmission fluids,and the like. These functional fluids are typically supplied as aconcentrate containing the antimicrobial composition and the othercomponents of the functional fluid. In the concentrate, a sufficientamount of the antimicrobial composition is provided such that the“working” functional fluid will contain a biocidally effective amountthereof. In order to satisfy this requirement, the concentrate for ametalworking fluid, for example, preferably contains a total amount ofup to about 15 weight percent, or more, of the antimicrobialcomposition, thereby providing up to about 1,500 ppm, or more, of theantimicrobial composition in the working fluid based upon a dilutionrate of the concentrate to the working fluid of between about 1:10 andabout 1:100.

The antimicrobial compositions of the present invention are also usefulin coatings such as paints, including indoor and outdoor householdpaints, industrial and commercial paints. Particularly advantageousresults are obtained when the antimicrobial compositions of the presentinvention are utilized, preferably in a total amount of between about0.01% and about 10% by weight based upon the weight of the paint, asin-can preservatives during storage and prior to the use of the paint.Although the antimicrobial compositions are also suitable for use inconjunction with marine paints for use, for example, on ship's hulls,care should be taken to avoid leaching of the soluble components of thecomposition out of the paint. Leaching can be suitably controlled by theuse of known encapsulation techniques.

The paint composition of the present invention may be used as a paintfor natural or synthetic materials, for example wood, paper, metals,textiles and plastics. It is particularly suitable as an outdoor paint,and is excellent for use as a marine paint.

In addition to paints, the antimicrobial composition of the presentinvention is also useful as an additive to other coatings known in theart. For example, the antimicrobial composition of the invention may beadded to a coating made from a base of a urethane polymer dispersionmixture, a hydroxylated methylmethacrylate acrylic polymer emulsion, anda crosslinker to form a coating that is resistant to microbial growth.

The antimicrobial composition of the present invention is also useful asan additive in adhesives, particularly water-based adhesives, to slow orstop microbial growth. The water-based nature of this type of adhesivealleviates the use and disposal of toxic organic compounds. Governmentregulation of the use and disposal of toxic organic substances hasforced many manufacturers to turn to water-based compositions. Inaddition, the water-based nature of this type of adhesive compositionresults in less volatile organic fumes being given off duringapplication and drying processes.

In one embodiment, the antimicrobial composition of the presentinvention may be added to a water-based adhesive base made from, amongother things, a combination of water-based aliphatic urethane resins. Inanother embodiment, the antimicrobial composition of the presentinvention may be added to a water-based adhesive base made from, amongother things, styrene-butadiene/latex (termed “SBR”) dispersion and anaqueous aliphatic polyurethane dispersion. As an example, the followingadhesive base medium may be used:

COMPONENT WET PARTS Oil 55.0 Hydrocarbon resin 45.0 Rosin Acid 10.0Surfactant 1.6 Urea 2% dry/dry Potassium Hydroxide 40.0 clay slurry 190SBR latex 94 Polyacrylate thickener 18.0

It will be appreciated, however, that any adhesive base may be used incombination with the antimicrobial composition of the present invention.

The antimicrobial composition of the present invention may also be addedto a sealant or an elastomer to provide control or eliminate microbialgrowth in those compositions. Known sealant or elastomer compositionstypically include a base medium made from urethane, polyurethane, or aurethane prepolymer, and are frequently combined with catalysts or otheragents to give the sealant or elastomer composition desired qualities.Other sealants and elastomers are known to be made from conjugateddienes, styrene-butadiene copolymers, styrene polymers, randomcopolymers of conjugated dienes and vinyl aromatic hydrocarbons,chloroprenes (e.g., neoprenes), isoprenes (e.g., natural latex),polyacrylates, and polysiloxanes (e.g., silicone rubbers). Examples ofsealant and elastomer base compositions are provided in U.S. Pat. Nos.4,374,237; 4,687,533; 4,374,237; 5,844,021; 4,410,644; 4,595,724; and4,925,894.

The compositions of the present invention are useful, in any of thevariety of applications described herein, as disinfectants andpreservatives, in a liquid or spreadable solid form, alone or incombination with an inert carrier such as water, liquid hydrocarbons,ethanol, isopropanol, or the like. The antimicrobial composition of thepresent invention is particularly useful in a soap, skin care, orcosmetic base to act as a preservative. The composition of the inventioncan be employed using conventional procedures to control bacteria andfungi in various substrates, and can be applied to bacterial or fungalorganisms or their substrates in an antimicrobial amount by conventionalprocedures such as spraying, dipping, drenching impregnation, and thelike.

The composition of the present invention is also useful as apreservative for wood or other cellulose-based materials, such aslumber, paper, cardboard, and the like, where microbial growth canoccur. Examples of uses of the present invention in the preservation ofwood and cellulose-based materials include, but are not limited to,lumber found on docks, ship hulls, patio decks, storage pallets, orother building and/or structural materials. The composition of thepresent invention may also be used as a preservative for detergentsand/or surfactants, such as ionic, nonionic, and zwitterionic detergentsor surfactants commonly known in the art and in which microorganismgrowth is problematic

The composition of the present invention may also be used as apharmaceutical composition to control the growth of any of the abovemicrobial organisms in a patient suffering from their systemicinfection. The pharmaceutical composition of the invention is preferablyadministered internally, e.g., intravenously, in the form ofconventional pharmaceutical preparations, for example in conventionalenteral or parenteral pharmaceutically acceptable carriers, such aswater, gelatin, lactose, starch, magnesium stearate, talc, plant oils,gums, alcohol, Vaseline, or the like. The pharmaceutical composition canbe in conventional solid forms, for example, tablets, dragees,suppositories, capsules, or the like, or conventional liquid forms, suchas suspensions, emulsions, or the like. If desired, they can besterilized and/or contain conventional pharmaceutical adjuvants, such aspreservatives, stabilizing agents, wetting agents, emulsifying agents,buffers, or salts used for the adjustment of osmotic pressure. Thepharmaceutical preparations may also contain other therapeuticallyactive materials. The pharmaceutical preparation of the invention shouldinclude an amount of the compound of the invention effective forantimicrobial activity. The effective dosage will depend on theantimicrobial activity and toxicity of the particular compound employedand is thus within the ordinary skill of the art to determine for anyparticular host mammal or other host organism. Suitable dosages may be,for example, in the range of about 0.5-15 mg per kg for a human being.

The present invention permits the use of reduced amounts of thepyrithione primary biocide, in conjunction with a water-soluble metalsalt co-biocide that is less expensive than the primary biocide, therebyproviding an antimicrobial composition that is inexpensive to produceand that possesses the above-mentioned characteristic of enhancedantimicrobial effectiveness against a variety of microorganisms.

The following examples are intended to illustrate, but in no way limitthe scope of the present invention. All parts and percentages are byweight and all temperatures are in degrees Celsius unless explicitlystated otherwise.

EXAMPLES Example 1 The Effect of 0.5 ppm Cu (II) on the MinimumInhibitory Concentration (MIC) of Sodium Pyrithione (NaPT)

NaPT and copper pyrithione (CuPT₂) were serially diluted in microtiterplates in Tryptic Soy Broth (TSB). NaPT was also diluted in TSB amendedwith 1 ppm of Cu (II) (CuSO₄.5H₂O). Equal volumes of bacterialsuspension (10⁶ bacteria per milliliter of TSB) containing Pseudomonasaeruginosa ATCC 9027 or fungal spore suspension (10⁵ spores permilliliter of TSB) containing Aspergillus niger ATCC 6275 or species ofFusarium and Cephalosporium isolated from contaminated metalworkingfluid were added to each microtiter plate well, and the plates wereincubated at 28° C. Controls were prepared for cultures inoculated intoTSB with and without Cu (II). After a period of 4 to 8 days, the lowestconcentration of biocide causing the inhibition of visible growth wasobserved. The results are shown in Table 1.

As shown in Table 1, Cu (II) had no effect by itself or on the MIC ofNaPT against the bacterium, but it reduced the MIC_(NaPT) four tosixteen-fold for the fungi. The pH of the broth medium was notinfluenced by the copper ion.

The antifungal effect of CuPT₂ for Aspergillus niger was greater thanthat of NaPT. The molar MIC of CuPT₂ (0.051 mM) was one seventeenth ofthat of NaPT. However, the amount of CuPT₂ (0.008 mM) theoreticallyformed in the mixture (0.5 ppm Cu (II)+8 ppm NaPT) was significantlyless than the MIC_(CuPT2). Thus, the enhancement of NaPT biocidalactivity cannot be attributed simply to the formation of the more activeCuPT₂ species.

TABLE 1 MIC (ppm) NaPT NaPT Test Organism * Cu (II) (without Cu) (with0.5 ppm Cu) CuPT₂ Bacteria: Pseudomonas >0.5 256 256 >1024 aeruginosaFungi: Aspergillus >0.5 128 8 16 niger Fusarium sp. >0.5 256 8 —Cephalosporium >0.5 64 16 — sp. * P. aeruginosa was incubated 5-6 days;A. niger was incubated 7-8 days; Fusarium and Cephalosporium wereincubated 5 days.

Example 2 Interactions of Pyrithione Salts and Zn(II) Ion: Zone ofInhibition Test

Cultures of bacteria were grown for 24 hr. on Tryptic Soy Agar (TSA),and suspensions containing 10⁸ cells per milliliter of sterile waterwere prepared. TSA plates were inoculated with sterile cotton swabs, andsterile 6.5 mm paper discs soaked with solutions containing solutions of0.1351 pyrithione (NaPT and the MgSO₄.3H₂O adduct of2,2′-dithiopyridine-1,1′-dioxide (MDS) in water, or zinc pyrithione(ZPT) in dimethylsulfoxide (DMSO)), 0.10% ZnCl₂, or a 1:1 molar mixtureof pyrithione and ZnCl₂. The discs were applied, and the plates wereincubated at 28° C. for 24 hr. The diameter of each zone of inhibitionwas measured with a ruler. The results are shown in Table 2.

As shown in Table 2, zinc chloride, by itself produced no zone ofinhibition for any of the three cultures and decreased the zone ofinhibition for some mixtures, but it increased the zone of inhibition ofMDS for Pseudomonas aeruginosa, indicating a favorable effect.

TABLE 2 Zone of Inhibition (mm) Staphylococcus Escherichia Pseudomonasaureus coli aeruginosa Test Solution ATCC 27217 ATCC 10536 NCIMB 6749DMSO 0 0 0 ZnCl₂, 0.1% 0 0 0 NaPT, 0.135% 31 35 8 ZPT, 0.135% 27 31 10MDS, 0.135% 28 31 0 NaPT, 0.135% + 27 24 8 ZnCl₂, 0.1% ZPT, 0.135% + 2627 10 ZnCl₂, 0.1% MDS, 0.135% + 28 32 9 ZnCl₂, 0.1%

Example 3 Interactions of Pyrithione Salts and Zn(II) and Ag(I) Ion:Checkerboard Minimum Inhibitory Concentration Test

Mixtures of pyrithione and zinc or silver in various proportions weretested for relative efficacy by a modification of the proceduredescribed by Dougherty, et al.

To evaluate Zn ion (Table 3a), aqueous stock solutions of pyrithione andzinc salts (ZnSO₄ or ZnO) and mixtures of the two were serially dilutedin TSB in microtiter plates. Equal volumes of bacteria (10⁶ cells/ml) orfungi (10⁵ spores/ml) were added to each microtiter plate well. Theplates were incubated at 28 C for 3 days (bacteria) or 5 days (fungi),and the minimum inhibitory concentration (MIC) of biocide wasdetermined. The Fractional Inhibitory Concentration (FIC=concentrationof biocide in an inhibitory mixture divided by the MIC of the purebiocide) was determined, and the FIC Index (sum of the two FIC's) wascalculated. The type of interaction was categorized according to themagnitude of the Index: Synergistic (<1), Additive (1), or Antagonistic(>1).

TABLE 3a Interaction of Pyrithiones with Zinc Salts MIC (ppm) TestOrganism Pyrithione salt Zn(II) Pyrithione Zn(II)/pyrithione FIC IndexStaphylococcus NaPT + ZnSO₄ 200 0 — — aureus 50 ≦1 ≧50/1    ≦0.5  ATCC27217 25 ≦1 ≧25 ≦0.8  12.5 2 6/1   0.6 6.3-0.8 4 2/1-1/5  1.0 0 4 — —ZPT + ZnSO₄ 200 0 — — 50 1 50/1   0.5   25-12.5 2 13/1-6/1   0.6-0.66.3-0.8 4 2/1-1/5  1.0 0 4 — — MDS + ZnSO₄ 200 0 — — 50 1 50/1   0.4 252 13/1   0.3 12.5-6.3  4 3/1-2/1  0.5-0.6 3.1-0.8 8  1/3-1/10  1.0 0 8 —— Pseudomonas NaPT + ZnSO₄ >200 0 — — aeruginosa 50 8 6/1  <0.3 NCIMB6749 25 16 2/1  <0.3 12.5 64 1/5  <0.6 6.3-0.8 128  1/20-1/160 <1.0 0128 — — ZPT + ZnSO₄ >200 0 — —   50-12.5 16 3/1-1/1 <(0.1-0.3) 6.3 1281/20 <0.5 3.1-0.8 256  83/1-320/1 <1.0 0 256 — — MDS + ZnSO₄ <200 0 — —50-25 32 2/1-1/1 <(0.2-0.3) 12.5 128 1/10 <0.2 6.3 512 1/81 <0.5 3.1-0.81024  1/330-1/1280 <1.0 0 1024 — — Fusarium sp. NaPT + ZnSO₄ >200 0 — — 50-6.3 51 1/1-1/8 <(0.2-0.4) 3.1-1.6 103 1/33-1/64 <0.3 0.8 205  1/256<0.5 0 411 — — ZPT + ZnSO₄ <200 0 — — 50-25 256  1/5-1/10 <(4.1-4.3)12.5 128 1/10 <2.1 6.3 64 1/10 <1.0 3.1 128 1/41 <2.0 1.6-0.8 641/40-1/80 <1.0 0 64 — — MDS + ZnSO₄ >200 0 — —  50-6.3 115  ½-1/18<(0.1-0.3) 3.1 230 1/75 <0.2 1.6 461  1/288 <0.3 0.8 1843  1/2300 <1.00 >1843 — — Ps. aeruginosa ZPT + ZnO >1645 0 — — ATCC 9027 51 64 1/1  <0.16 0 512 — — Aspergillus ZPT + ZnO >1645 0 — — niger 206 32 6/1  <0.63 ATCC 6275 0 64 — —

Consistent with the previous example, Zn(II) enhanced the activity ofMDS. The FIC Indices were <1 for the Zn(II)/MDS range of from 1/288 to50/1 for two bacteria and one fungus (Table 3a). However, theinteraction was not technically synergistic, because the Zn²⁺ reagent byitself produced no detectable effect at the concentrations used. Incontrast to results in Example 1, Zn(II) surprisingly enhanced byactivities of the two other pyrithiones. The FIC Indices were <1.0 forthe Zn(II)/pyrithione range of from 1/256 to ≧50/1.

The zinc complex of pyrithione (ZPT) and the sodium salt of pyrithione(NaPT) and silver salts were tested in various ratios according to thecheckerboard procedure described above. Briefly, mixtures of pyrithionesand silver ions in various proportions were tested for relative efficacyby the modified procedure of Dougherty et al. described above. Aqueousstock solutions of pyrithiones and silver salts (Ag₂O or AgCl) andmixtures of the two were serially diluted in microtiter plates intryptone soy broth (TSB), pH 7.3 (bacteria and Candida) or UshijimaMedium (Microbiol. Immunol. 25:1109, 1981), pH 5.5 (Pyrosporum). Equalvolumes of bacteria (10⁶ cells/ml) or fungi (10⁵ spores/ml) were addedto each microtiter plate well. The plates were incubated at 35° C. for 1to 2 days, and the minimum inhibitory concentration (MIC) of biocide wasdetermined. The Fractional Inhibitory Concentration (FIC, concentrationof biocide in an inhibitory mixture divided by the MIC of the purebiocide) of each biocide was determined, and the FIC Index (“S”, the sumof the two FICs) was calculated. The type of interaction is categorizedaccording to the magnitude of the Index, where synergistic is defined as<1, additive is approximately 1, and antagonistic is >1.

TABLE 3b Interaction of Pyrithiones with Silver Salts MIC (ppm) Ratio(s)Organism ZPT NaPT Ag⁺¹ Ion (PT/Ag⁺¹) S Staphylococcus (Source: Ag₂O)aureus 27217 4 — 0 — — 4 — 0.9-3.7 4.30-1.07 1.03-1.13 2 — 7.4 0.27 0.751 — 14.9 0.07 0.75 0 — 29.8 — — — 4 0 — — — 4 0.9 4.30 1.03 — 21.90-7.40 1.05-0.26 0.56-0.75 — 0.25 14.9 0.02 0.56 — 0 29.8 — —Escherichia coli 8 — 0 — — 10536 2 — 0.9 2.15 0.75   0.25 — 0.9 0.250.53 0 — 1.9 — — — 16 0 — — — 1 0.9-1.9 1.02-0.54 0.19-0.31 — 0.5 3.70.13 0.53 — 0 7.4 — — Staphylococcus (Source: AgCl₂) aureus 27217 — 8 0— — — 16 0.15 106.24  2.03 — 8 0.3-1.2 26.56-6.64  1.03-1.13 — 2 2.30.86 0.50 — 0.25 4.7 0.05 0.53 — 0 9.5 — — Escherichia coli — 16 0 — —10536 — 16 0.8-1.5 21.24-10.62 1.04-1.08 — 4 2.3 1.77 0.38 — 1 2.3 0.440.18 — 0.5 4.5 0.11 0.27 — 0.13 9.79 0.01 0.53 — 0 18.8 — — Pseudomonas— 256 0 — — aeruginosa — 256 0.1-3.8 340.00-68.00  1.0-2.0 9027 — 2-10.8 2.36-1.18 0.27-0.26 —  4-≦1 1.9 2.12-0.53  0.52-≦0.56 — 8-2 3.82.12-0.53 1.03-1.01 — 0 3.8 — — Candida albicans (Source: AgCl₂) 10251 —16 0 — — — 16 0.8-1.5 21.25-10.62 1.08-1.16 — 8 2.3 3.54 0.74 — 2 4.50.44 0.59 — 0 9.8 — Pityrosporum — 4 0 — — ovale 1452 — 2 0.2 13.28 0.63 — 1 0.3 3.32 0.50 — 0.5 0.6 0.83 0.63 — 0 1.2 — —

As shown in Table 3b, both of the silver salts and pyrithiones exhibitedsynergistic inhibition of both Gram positive and Gram negative bacteriaand yeast, including the causative agent of dandruff.

Example 4 Efficacy of a Mixture of NaPT and Zn or Cu Ions in aMetalworking Fluid Emulsion

A mixture of 250 ppm (v/v) of NaPT (40% active) and 10 ppm of Cu (II)(CuSO₄.5H₂O) or Zn(II) (ZnSO₄.7H₂O) was added to a metalworking fluid(MWF). An emulsion was prepared from a 5% dilution of a concentrate,consisting of mineral oil (83.5%), sulfonated hydrocarbon (10.7%), oleicacid (1.0%), triethanolamine (0.8%), methyl tallowate (3.0%), andpropylene glycol ether (1.0%) and dispensed into Erlenmeyer flasks. Eachsample was challenged twice over a period of 40 days with 10⁷ calls ofbacteria and 10⁵ fungal spores per milliliter of emulsion. The challengeconsisted of seven strains of bacteria and 2 strains of fungi originallyisolated from contaminated metalworking fluid: Pseudomonas rubescensNCIMB 12202, Pseudomonas stutzeri sp., Pseudomonas fluorescens NCIMB12202, Pseudomonas aeruginosa CIMB 6749, Pseudomonas olevorans NCIMB6576, Alcaligenes faecalis sp., Citrobacter freundii CIMB 12203,Fusarium sp., and Cephalosporium sp. The fluids were agitatedcontinuously on a rotary shaker, and surviving bacteria and fungi wereenumerated periodically by viable plate counts on Tryptic Soy Agar.

Cu(II) (10 ppm), by itself, had little effect on reducing the growth offungi. However, the combination of Cu(II) and NaPT exhibited an enhancedfungicidal effect (FIG. 2). As shown in FIG. 1, Cu(II), by itself,significantly reduced bacterial counts until the second challenge,whereas Cu(II)+NaPT exhibited only a slight improvement over theantibacterial efficacy of NaPT, presumably the result of the conversionof NaPT to the less water-soluble Cu salt of pyrithione.

The favorable effect of Zn(II) on NaPT efficacy was much more pronouncedthat the effect observed with Cu (II). Antibacterial and antifungalactivities were significantly increased and persisted through the secondchallenge (FIGS. 1 and 2). Concentrations of 1 and 100 ppm of Zn(II)produced proportional enhancements of NaPT efficacy.

Example 5 Investigation of the Efficacy of a Mixture of Pyrithione andMetal Salts to Inhibit the Growth of Biofilms in Metalworking Fluids

Experiments were conducted to investigate the efficacy of thecomposition of the present invention to inhibit the survival, growth,and proliferation of free-living and biofilm populations of bacteria andfungi in metalworking fluids. Test microorganisms included two bacterialspecies, P. aeruginosa 9027 and E. coli 8739, and a fungal isolate,Fusarium sp. Metalworking fluids (MWF) employed included 5% soluble oilMWF, 5% semi-synthetic MWF, or 5% synthetic MWS. For testing againstbacteria, metalworking fluids were supplemented with 2%(weight-to-weight ratio (w:w)) of 5 g/L yeast extract (Difco),Metalworking fluids were supplemented with 2% (weight-to-weight (w:w))of Tryptic Soy Broth (Difco) for fungal tests.

For each experiment, three ml of a 5% metalworking fluid was added toeach of twelve, sterile, 16 mm×150 mm glass culture tubes. Each tubecontained one polycarbonate disc (0.5″ dia×0.125″ thick) which served asa surface for biofilm attachment. For bacterial tests, P. aeruginosa9027 or E. coli 8739 were added to the tubes to final concentrations of10⁷ cells/ml. Fusarium sp. was added to the tubes to finalconcentrations of 10⁵ spores/ml for the fungal tests. Tubes incubatedfor 3 days at 28° C. and 180 rpms.

After incubation, three replicate culture tubes were randomly assignedto four treatment groups which received the following treatments:untreated control, 100 ppm or 50 PPM pyrithione (final concentration),10 ppm Zn (II) (ZnSO₄.7H₂O) (final concentration), or 100 PPM or 50 PPMpyrithione+10 ppm Zn (II) (final concentrations). After the treatmentsadditions were performed, the culture tubes resumed incubation at 28°C., 180 rpms for an additional 4 days.

After 4 days, culture tubes were removed from the incubator and viablecounts of organisms from the bulk MWF fluid and the biofilm weredetermined using serial dilution and drop plating techniques. Forbiofilms, polycarbonate discs were removed from tubes, dip-rinsed inthree successive washes of de-ionized water to remove loosely attachedcells, and transferred to 25 mm×150 mm culture tubes containing 10 ml ofsterile, de-ionized water. Biofilms were removed from discs andresuspended by vortexing tubes for 30 seconds. Bacteria were plated onto R2A Agar plates and incubated at 37° C. Fungi were plated onto MaltAgar plates and incubated at 28° C. Mean colony forming units per ml(for bulk) and per square cm (cm²) biofilm were determined for eachexperimental treatment.

Tables 4a-b show the results of experiments testing the efficacy of 100PPM NaPT or 50 PPM ZPT in combination with 10 PPM Zn(II) ions againstfree-living and biofilm microorganisms in three metalworking fluids andin Tryptic Soy Broth (TSB). The microorganisms challenged in these testsinclude two bacterial isolates, Pseudomonas aeruginosa 9027 andEscherichia coli 8739, and a fungal isolate of Fusarium sp. In additionto displaying the microorganism, metalworking fluid type, and biocideconcentrations used in each test, Tables 4a and 4b display mean numberof viable free-living microorganisms per ml and of mean number of viablebiofilm microorganisms per cm². Two way analysis of variance withreplication of log transformed data was used to statistically test forsynergy (pyrithione X zinc interaction).

TABLE 4a Efficacy of 100 PPM Sodium Pyrithione + 10 PPM Zn (II) AgainstFree-Living Organisms in Metalworking Fluids. cells/ml 100 PPM NaPTMicroorganism Medium Untreated 100 PPM NaPT 10 PPM Zn (II) 10 PPM Zn(II) P. aeruginosa 9027 5% solub. oil 1.1 × 10⁵ 8.1 × 10⁵ 7.2 × 10⁵  2.6× 10³* 5% solub. oil 1.6 × 10⁵ 1.3 × 10⁶ 1.5 × 10⁶  3.0 × 10³* 5% solub.oil 1.3 × 10⁶ 2.1 × 10⁶ 1.1 × 10⁵ 0* 5% semisynth 1.4 × 10⁵ 6.8 × 10⁴1.6 × 10⁴ 0* 5% semisynth 1.2 × 10⁵ 1.9 × 10⁵ 2.4 × 10⁵  3.8 × 10²* 5%semisynth 8.9 × 10⁴ 2.3 × 10⁴ 8.0 × 10⁴ 20*  5% synthetic 9.1 × 10⁶ 7.8× 10⁶ 2.7 × 10⁴ 9.8 × 10⁴ 5% synthetic 3.6 × 10⁶ 7.0 × 10⁵ 8.1 × 10³ 3.5× 10⁵ 5% synthetic 6.6 × 10⁶ 5.4 × 10⁵ 1.1 × 10⁶ 6.5 × 10⁵ E. coli 873910% TSB 1.3 × 10⁹ 9.1 × 10⁸ 5.8 × 10⁸ 6.0 × 10⁸ 5% solub. oil 1.0 × 10⁸5.3 × 10⁷ 2.1 × 10⁴ 2.4 × 10⁴ 5% semisynth. NG NG NG NG 5% semisynth. NGNG NG NG 5% synthetic 1.8 × 10⁵ 3.7 × 10³ 2.2 × 10³  3.6 × 10³* 5%synthetic 1.1 × 10⁶ 0 0 0  Fusarium sp. 100% TSB 2.0 × 10⁶ 0 3.4 × 10⁶0  5% solub. oil 4.8 × 10⁷ 4.2 × 10⁶ 2.4 × 10⁶ 0* 5% semisynth. 5.1 ×10⁵ 2.8 × 10⁵ 4.6 × 10⁵ 0* 5% synthetic 1.3 × 10⁷ 6.0 × 10⁶ 8.7 × 10⁶ 0*NG, no growth *statistically significant interaction, P < 0.05

TABLE 4b Efficacy of 100 PPM Sodium Pyrithione + 10 PPM Zn (II) AgainstBiofilm Organisms in Metalworking Fluids. cells/cm² 100 PPM NaPTMicroorganism Medium Untreated 100 PPM NaPT 10 PPM Zn (II) 10 PPM Zn(II) P. aeruginosa 9027 5% solub. oil 2.3 × 10⁴ 2.6 × 10⁴ 2.9 × 10⁴  2.5× 10²* 5% solub. oil 6.9 × 10³ 2.6 × 10⁴ 1.6 × 10⁴  2.4 × 10²* 5% solub.oil 1.0 × 10⁴ 2.0 × 10⁵ 7.7 × 10³ 70*  5% semisynth. 5.3 × 10⁴ 4.1 × 10⁴1.7 × 10⁵ 3.9 × 10² 5% semisynth. 4.7 × 10³ 1.1 × 10³ 4.3 × 10³ 7* 5%semisynth. 4.3 × 10³ 4.9 × 10² 2.9 × 10³ 0* 5% synthetic 3.6 × 10⁵ 4.1 ×10⁵ 3.6 × 10² 8.9 × 10⁴ 5% synthetic 2.1 × 10⁵ 9.9 × 10⁴ 1.6 × 10³ 3.2 ×10⁵ 5% synthetic 3.0 × 10⁵ 2.1 × 10⁵ 1.4 × 10⁶ 8.1 × 10⁵ E. coli 873910% TSB 1.6 × 10⁶ 1.4 × 10⁶ 6.5 × 10⁵ 8.6 × 10⁵ 5% solub. oil 2.8 × 10⁵1.6 × 10⁵ 1.8 × 10³ 3.3 × 10³ 5% semisynth. NG NG NG NG 5% semisynth. NGNG NG NG 5% synthetic 3.1 × 10⁴ 77 55 2.0 × 10² 5% synthetic 1.6 × 10³1.1 × 10² 1.1 × 10² 26*  Fusarium sp. 100% TSB 5.4 × 10⁴ 96 3.3 × 10⁴6.8 × 10² 5% solub. oil 6.8 × 10⁴ 4.6 × 10⁵ 4.0 × 10⁴   5.3* 5%semisynth. 23 18 27 0* 5% synthetic 1.3 × 10⁵ 7.3 × 10⁴ 1.4 × 10⁵  6.2 ×10²* NG, no growth *statistically significant interaction, P < 0.05

As shown in Tables 4a and 4b, cultures treated with 100 PPM NaPT aloneor with 10 PPM Zn (II) alone display usually less than an order ofmagnitude fewer viable free-living and biofilm P. aeruginosa andFusarium sp. cells compared to untreated cultures in all threemetalworking fluids. One exception to this, however, includes theeffectiveness of treatment with 10 PPM Zn (II) alone against P.aeruginosa in this synthetic fluid which decreased viable counts intreated cultures by about two orders of magnitude compared to untreatedcontrols. Also notable, E. coli was sensitive to 100 PPM NaPT alone inthis synthetic fluid and to 10 PPM Zn (II) alone in these soluble oiland synthetic metalworking fluids. The effectiveness of biocides areknown to be influenced by the specific formulations of metalworkingfluids and may vary within and between metalworking fluid types.

In contrast to the ineffectiveness of 100 PPM NaPT or 10 PPM Zn (II)alone against P. aeruginosa and Fusarium, cultures treated with acombination of 100 PPM NaPT and 10 PPM Zn (II) showed from 1.5 up to 6.0orders of magnitude fewer viable counts of free-living and biofilm cellsof P. aeruginosa and Fusarium than untreated control cultures. Ananalysis of variance indicated the presence of synergistic antimicrobialactivities (P<0.05) between 100 PPM NaPT and 10 PPM Zn (II) ions againstP. aeruginosa free-living cells and biofilm cells in soluble oil andsemi-synthetic metalworking fluids and against free-living and biofilmFusarium sp. in soluble oil, semi-synthetic, and synthetic metalworkingfluids.

Table 5 shows the mean numbers of viable P. aeruginosa biofilm cellspresent on different types of growth surfaces when grown for three daysin the different types of metalworking fluids. These results suggestthat soluble oil and synthetic metalworking fluids support biofilms ofgreater cell density than semi-synthetic fluids. Furthermore, rubbersurfaces tend to allow greater biofilm growth than stainless steel orpolycarbonate surfaces.

TABLE 5 Mean cfu/cm² of P. aeruginosa when grown on selected surfacecompositions Metalworking Fluid Type Surface Soluble Oil Semi-SyntheticSynthetic Stainless Steel 2.8 × 10⁴ 6.9 × 10³ 4.6 × 10⁶ Rubber 2.8 × 10⁷1.2 × 10⁶ 1.6 × 10⁷ Polycarbonate 6.1 × 10⁶ 5.6 × 10³ 6.5 × 10⁵

Microorganisms are known to adhere to and/or form biofilms on all typesof surfaces. Therefore, additional experiments were conducted toinvestigate the efficacy of the composition of the present invention toinhibit the survival, growth, and proliferation of free-living andbiofilm bacteria attached to different surface types in metalworkingfluids. As described in the previous experiments, three ml of a 5%soluble oil metalworking fluid was added to sterile, 16 mm×150 mm glassculture tubes. Tubes contained polycarbonate disc (0.5″ dia×0.125″thick), neoprene rubber discs (0.5″ dia×0.25″ thick), or steel washers(0.4″ outer diameter, 0.2 inner diameter, X 0.03″ thick). P. aeruginosa9027 was added to the tubes to final concentrations of 10⁷ cells/ml andthe tubes incubated for 3 days at 28° C. and 180 rpm. For each surfacetype (polycarbonate, rubber or steel), three replicate tubes wererandomly assigned to one of four treatment groups: untreated control,100 ppm sodium pyrithione (final concentration), 2.5 ppm Zn(II)(ZnSO₄.7H₂O) (final concentration), or 100 PPM sodium pyrithione+2.5 ppmZn(II) (final concentrations). Culture tubes resumed incubation at 28°C., 180 rpms for an additional 4 days. Sampling of bulk fluid andbiofilm organisms is as described above. Results of this experiment areshown in Tables 6a and 6b.

TABLE 6a Efficacy of Sodium Pyrithione and Zinc Combination AgainstFree-Living P. aeruginosa in the Bulk Fluid of 5% Soluble OilMetalworking Fluid. cells/ml 100 PPM NaPT Organism Surface Untreated 100PPM NaPT 2.5 PPM Zn(II) 2.5 PPM Zn(II) P. aeruginosa 9027 Polycarbonate3.7 × 10⁴ 4.9 × 10⁵ 3.1 × 10⁵ 2.6 × 10³* Rubber 2.0 × 10⁶ 50 8.0 × 10⁵0* Steel 6.1 × 10⁵ 3.5 × 10⁶ 2.1 × 10⁶ 2.0 × 10²* *statisticallysignificant interaction, P < 0.05

TABLE 6b Efficacy of Sodium Pyrithione and Zinc Combination Against P.aeruginosa in the Biofilm of 5% Soluble Oil Metalworking Fluid.cells/cm² 100 PPM NaPT Organism Surface Untreated 100 PPM NaPT 2.5 PPMZn(II) 2.5 PPM Zn (II) P. aeruginosa 9027 Polycarbonate 1.3 × 10⁴ 2.8 ×10⁴ 4.7 × 10⁴ 9.7 × 10²* Rubber 3.0 × 10⁷ 5.3 × 10² 2.4 × 10⁷ 8.0 × 10² Steel 4.2 × 10³ 1.1 × 10⁵ 1.5 × 10⁴ 83* *statistically significantinteraction, P < 0.05

The results shown in Tables 6a and 6b show that cultures treated withthe combination of 100 PPM NaPT and 2.5 PPM Zn (II) had fewer viablefree-living cells, and fewer viable biofilms cells when grown onpolycarbonate, rubber, or steel, respectively, than untreated cultures.The efficacy of the mixture of 100 PPM NaPT and 2.5 PPM Zn(II) alsodemonstrated a much greater efficacy against free-living and biofilmbacteria on polycarbonate and steel than NaPT or Zn(II) ions alone. Ananalysis of variance detected the presence of synergistic antimicrobialactivities (interaction; P<0.05) between 100 PPM NaPT and 2.5 PPM Zn(II)against free-living and biofilm cells in all cases, excepting biofilmsgrown on rubber surfaces. The efficacy of the combination of 100 PPMNaPT and 2.5 PPM Zn(II) ions against P. aeruginosa biofilms grown onvarious surface types is similar to that of the combination of 100 PPMNaPT and 10 PPM Zn(II) ions against biofilms grown on polycarbonate.This suggests that utilizing 2.5 PPM Zn(II) ions with 100 PPM NaPT willbe effective at disinfecting free-living cells and biofilms grown onbroad range of surface types and that the addition of 2.5 PPM Zn(II) to100 PPM NaPT is as about efficacious as adding 10 PPM Zn (II) ions.

Similar experiments were undertaken to test the efficacy of acombination of 100 PPM NaPT and 2.5 PPM Zn(II) against free-living andbiofilm cells of a bacterial consortia made up of several species ofbacteria often found in contaminated metalworking fluids. These bacteriaincluded Pseudomonas aeruginosa 9027, Pseudomonas putida sp.,Pseudomonas fluorescens NICMB 12201, Pseudomonas rubescens NICMB 12202,Escherichia coli 8379, Citrobacter freundii NCIMB 6576, and Alcaligenesfaecalis sp. These experiments were conducted in all three types ofmetalworking fluids and biofilms were grown on polycarbonate, rubber,and stainless steel surfaces. The results of these experiments indicatethat in soluble oil and semi-synthetic fluids, treatment of cultureswith the combination of 100 PPM NaPT and 2.5 PPM Zn(II) reduced viablefree-living consortia cells by about five orders of magnitude andreduced viable biofilm cells by two orders of magnitude.

The efficacy of combinations of 100 ppm NaPT and 10 ppm of selectedother metal ions against P. aeruginosa free-living and biofilms cellsare shown in Table 7a, 7b, and 7c. These experiments were conducted inthree types of metalworking fluids and biofilms were grown onpolycarbonate surfaces. Tables 7a, 7b, and 7c display the average numberof viable free-living cells per ml and biofilm cells per squarecentimeter.

TABLE 7a Efficacy of 100 PPM Sodium Pyrithione and Various Metal IonsAgainst Free-Living and Biofilm P. aeruginosa in 5% Soluble OilMetalworking Fluid. NaPT NaPT NaPT NaPT NaPT NaPT 100 PPM + 100 PPM +100 PPM + 100 PPM + 100 PPM + 100 PPM + Cu (II) Fe (II) Mn (II) Mg (II)Na Co (II) Untreated 10 PPM 10 PPM 10 PPM 10 PPM 10 PPM 10 PPMFree-Living Cells/ml 4.0 × 10⁵ 2.4 × 10⁶ 2.1 × 10⁵ 1.2 × 10⁶ 4.4 × 10⁶9.1 × 10⁴ 1.0 × 10⁶ Biofilm Cells/cm² 1.0 × 10⁴ 6.1 × 10⁴ 9.3 × 10⁶ 6.6× 10⁶ 1.2 × 10⁷ 4.6 × 10⁶ 5.9 × 10⁶

TABLE 7b Efficacy of 100 PPM Sodium Pyrithione and Various Metal IonsAgainst Free-Living and Biofilm P. aeruginosa in 5% Semi-syntheticMetalworking Fluid. NaPT NaPT NaPT NaPT NaPT NaPT 100 PPM + 100 PPM +100 PPM + 100 PPM + 100 PPM + 100 PPM + Cu (II) Fe (II) Mn (II) Mg (II)Na Co (II) Untreated 10 PPM 10 PPM 10 PPM 10 PPM 10 PPM 10 PPMFree-Living Cells/ml 2.7 × 10⁴ 3.7 × 10⁴ 1.3 × 10⁵ 3.9 × 10³ 3.4 × 10⁵3.3 × 10³ 1.5 × 10⁵ Biofilm Cells/cm² 1.5 × 10⁵ 5.3 × 10⁵ 4.3 × 10⁵ 1.1× 10² 2.3 × 10⁵ 2.5 × 10⁴ 4.6 × 10⁴

TABLE 7c Efficacy of 100 PPM Sodium Pyrithione and Various Metal IonsAgainst Free-Living and Biofilm P. aeruginosa in 5% SyntheticMetalworking Fluid. NaPT NaPT NaPT NaPT NaPT NaPT 100 PPM + 100 PPM +100 PPM + 100 PPM + 100 PPM + 100 PPM + Cu (II) Fe (II) Mn (II) Mg (II)Na Co (II) Untreated 10 PPM 10 PPM 10 PPM 10 PPM 10 PPM 10 PPMFree-Living Cells/ml 3.8 × 10⁶ 2.6 × 10⁵ 4.9 × 10⁶ 9.6 × 10² 6.6 × 10⁵3.0 × 10⁴ 7.7 × 10⁵ Biofilm Cells/cm² 4.0 × 10⁵ 2.4 × 10³ 2.6 × 10⁶ 1.1× 10³ 7.1 × 10³ 7.9 × 10³ 1.1 × 10⁴

The results of these experiments show that, in soluble oil andsemi-synthetic fluids, cultures treated with 100 ppm NaPT and 10 ppm ofCu(II), Fe(II), Mg(II), Na, or Co(II) contain about the same or highernumbers of viable free-living and biofilm cells as untreated cultures.The combination of 100 ppm NaPT and 10 ppm Mn(II), however, reducesviable biofilm cell counts by three orders of magnitude. In syntheticfluids, cultures treated with 100 ppm NaPT and 10 ppm of any metal ionother than Fe(II) displayed at two orders of magnitude less viablebiofilm cells than untreated culture. Because 100 ppm NaOM alone haslittle effectiveness against P. aeruginosa biofilm cells in metalworkingfluids, these results suggest that the addition of a broad range ofmetal ions to 100 ppm NaPT can increase the efficacy of NaPT insynthetic metalworking fluids.

Example 6 Effect of Zn²⁺ on Efficacy of Zinc Pyrithione in a Soluble OilMetalworking Fluid

The novel effects of Zn ion on pyrithione antimicrobial activity isillustrated in this example. In previous examples, metalworking fluidswere dosed with a mixture of 100 ppm of NaPT and 10 ppm of Zn²⁺. Thetheoretical amount of ZPT generated in the fluid would be 48.5 ppm. Inthis example, 50 ppm of added ZPT was supplemented with an additional 10ppm of Zn²⁺ and compared with the NaPT/Zn mixture.

A metalworking fluid was amended with ZPT and Zn ion and challenged withseven cultures of bacteria and two cultures of fungi as describedpreviously. For comparison, samples of fluid amended with 50 ppm of thecopper salt of pyrithione (CuPT) and 10 ppm of Zn²⁺ were also tested.The results are shown in Table 8 expressed as CFU/ml.

TABLE 8 Effect of Zn²⁺ on Efficacy of Zinc Pyrithione in a Soluble OilMetalworking Fluid. 50 ppm 100 ppm 50 ppm CuPT + NaPT + 10 ppm 50 ppmZPT + 10 ppm 50 ppm 10 ppm DAY Blank 10 ppm Zn Zn ZPT Zn CuPT ZnBACTERIA (cfu/ml) 0 3.2 × 10⁷ 3.2 × 10⁷ 3.2 × 10⁷ 3.2 × 10⁷ 3.2 × 10⁷3.2 × 10⁷ 3.2 × 10⁷ 6 2.0 × 10⁷ 4.7 × 10⁶ 1.5 × 10³ 1000 10 1.5 × 10⁷ 1013 2.1 × 10⁷ 1.1 × 10⁷ 2.3 × 10⁴ 4400 10 9.7 × 10⁶ 10 20 2.3 × 10⁷ 7.2 ×10⁶ 3.0 × 10⁴ 7700 10 1.9 × 10⁶ 10 FUNGI (cfu/ml) 0 2.4 × 10⁵ 2.4 × 10⁵2.4 × 10⁵ 2.4 × 10⁵ 2.4 × 10⁵ 2.4 × 10⁵ 2.4 × 10⁵ 6 1.7 × 10⁵ 7.5 × 10⁴1.5 × 10⁴ 1000 5800 1000 690 13 2.2 × 10⁵ 3.5 × 10⁴ 10 10 90 680 830 201.5 × 10⁵ 2.2 × 10⁴ 100 10 10 370 880

As shown in Table 8, the bacterial data showed that Zn (II) ionssignificantly improved the activities of ZPT beyond the level expectedfrom the amount of ZPT generated in situ from added Zn and NaPT. Similarresults were obtained with CuPT. The phenomenon was not evident in thefungal data: ZPT and CuPT, alone were strongly fungicidal. Accordingly,this data suggests that Zn ion unexpectedly enhances the activities ofpyrithione biocides in general.

Example 7 Efficacy of 100 PPM NaPT And 15 PPM Zn (II) Ions AgainstFree-Living And Biofilm Associated Microorganisms in SimulatedMetalworking Fluid System

A five gallon, glass aquarium tank was disinfected with bleach and setup to simulate a recirculating metalworking fluid system. An aquariumpump was attached to the tank as a means of recirculating the fluidthrough the tank. To provide sampling surfaces for biofilm growth,stainless steel washer coupons (surface area, 1.2 cm²) and polycarbonatedisc coupons (surface area, 3.8 cm²) were attached to glass slide couponholders with double stick carpet tape. The coupon holders were thenattached by carpet tape to the floor and sides of the tank. Two steeland two polycarbonate coupons were placed on each holder. 12.5 liters ofdilute (1:20) semi-synthetic metalworking fluid was added to the tank.Bacteria were added to a final concentration of 10⁶ bacteria/ml. Thebacterial inoculum consisted of an equal number of cells fromPseudomonas aeruginosa 9027, Escherichia coli 8739, Pseudomonasfluorescens 12201, Pseudomonas rubescens 12202, and Pseudomonas putida.Fungal spores were added to the tank to final concentrations of 10⁴spores/ml. Fungal additions consisted of an equal number of spores fromFusarium sp. and Cephalosporium sp. metalworking fluid field isolates.Bacterial and fungal additions were repeated three times per week.

The tank was recirculated at room temperature (23° C.±2° C.) for 19 daysand then sampled for initial bacterial and fungal densities in the bulkfluid and biofilm. For the bulk fluid, samples from the tank wereserially diluted (1:10) in sterile, de-ionized water and spread platedfor bacterial and fungal counts on Tryptic Soy Agar plus 90 PPMcycloheximide and Malt Agar plus 900 PPM streptomycin plus 550 PPMPenicillin G, respectively. For biofilm samples, coupons holders wereremoved from the bottom and sides of the tank. Coupons were removed fromthe holders, dip rinsed in sterile water, and transferred to 25 mm×150mm glass disposal culture tubes containing 10 ml of sterile, de-ionizedwater. Biofilms were liberated from the coupons and resuspended byvortexing tubes at maximum speed for 30 seconds. Resuspended biofilmswere then serially diluted and plated for bacteria and fungal counts asdescribed for bulk fluid samples. 0.5 ml of slime material from thesides for the tank at the fluid-air interface were sampled by a sterile,needless syringe and resuspended in sterile, de-ionized water and byvortexing. Counts of bacterial and fungi in the slime samples were alsodetermined as described previously for bulk fluid samples. Plates wereincubated at 28° C. for two to three days and then scored for colonyforming units. For biofilm samples, excepting the slime material, colonyforming units per ml were converted to colony forming units per cm².

NaPT and Zn (II) ions (ZnSO₄.7H₂O) were added to the tank to finalconcentrations of 100 PPM and 15 PPM, respectively. The tank was allowedto recirculate for four days. At day 4 after NaPT and Zn (II) treatment,bacteria and fungal densities in the bulk fluid and biofilm weredetermined as described above for the initial sampling. Table 9 showsthe results of this experiment.

TABLE 9 The Efficacy Of 100 PPM NaPT And 15 PPM Zn (II) Ions AgainstFree-Living And Biofilm Associated Microorganisms In SimulatedMetalworking Fluid System. Pre-treatment Post-Treatment SampleBacteria/ml Fungi/ml Bacteria/ml Fungi/ml Bulk Fluid 1 1.3 × 10⁷ 7.0 ×10³ 1.3 × 10⁴ 0 2 1.2 × 10⁷ 6.0 × 10³ 1.4 × 10⁴ 0 Biofilm tank floorStainless steel 1 4.4 × 10⁶ 9.2 × 10⁴ 7.0 × 10³ 10 2 2.0 × 10⁶ 1.3 × 10⁵1.2 × 10⁴ 0 Polycarbonate 1 5.6 × 10⁶ 1.5 × 10⁵ 4.0 × 10⁴ 0 2 2.4 × 10⁶1.3 × 10⁵ 5.6 × 10⁴ 0 Biofilm tank side Stainless steel 1 2.3 × 10⁶ 1.1× 10⁴ 1.0 × 10⁴ 0 2 2.3 × 10⁶ 3.0 × 10⁴ 2.4 × 10⁴ 0 Polycarbonate 1 2.8× 10⁶ 2.0 × 10⁴ 2.8 × 10³ 0 2 2.0 × 10⁶ 1.6 × 10⁴ 2.2 × 10³ 0 Splasharea slime tank side 1 1.9 × 10⁵ 1.0 × 10⁴ 4.8 × 10³ 30

As shown in Table 9, treatment of the tank with 100 PPM NaPT and 15 PPMZn (II) ions resulted in a 1000-fold reduction in bacterial numbers anda 6000-fold decrease in fungal numbers in the bulk fluid. No fungalcould be detected in the bulk fluid. Furthermore, treatment reducedbiofilm bacteria counts by about 100 to 1000-fold and biofilm fungalcounts by 10,000 to 100,000-fold. Nearly no fungi could be detect in thesubmerged biofilms or in the slime material at the air-fluid interface.This data suggest that the composition of the present invention isoperative under conditions similar to those found in the field.

Example 8 Efficacy of Various Mixtures of NaPT and Zn(II) Ions AgainstMicroorganisms in Metalworking Fluids

Sterile, glass, disposable culture tubes (16 mm×150 mm) containing threeml of 5% metalworking fluid were set up for each of the followingmetalworking fluid types: soluble oil, semi-synthetic, and synthetic. Toeach tube, bacteria were added to a final concentration of 10⁷bacteria/ml. The bacterial inoculum consisted of an equal number ofcells from Pseudomonas aeruginosa 9027, Escherichia coli 8739,Pseudomonas fluorescens 12201, Pseudomonas rubescens 12202, andPseudomonas putida. Fungal spores were added to each tube to finalconcentrations of 10⁵ spores/ml. Fungal additions consisted of an equalnumber of spores from Fusarium sp. and Cephalosporium sp. metalworkingfluid field isolates. Tubes were incubated 28° C. and 180 rpms for sevendays.

Pretreatment cell densities of bacteria and fungi were determined byserially diluting fluid samples (1:10) in sterile, de-ionized water andspread plating the dilutions for bacterial and fungal counts on TrypticSoy Agar plus 90 PPM cycloheximide and Malt Agar plus 900 PPMstreptomycin plus 550 PPM Penicillin G, respectively. Plates wereincubated at 28° C. for two to three days and then scored for colonyforming units (cfu). After initial sampling, tubes received thefollowing biocide treatments. For each fluid type, an untreated controltube containing no NaPT or Zn(II) ions was established. NaPT alone wasadded to construct several NaPT control tubes with no zinc present.Similarly, Zn (II) ions (ZnSO₄.7H₂O) alone were used to set up severalzinc control tubes containing no NaPT. Test treatment tubes consistingof mixtures of NaPT and Zn (II) ions were also constructed. Tubesresumed incubation at 28° C. and 180 rpms and were sampled for bacterialand fungal densities on days 1, 2, 4, or 7 post-treatment. Experimentalresults are shown in Tables 10a and 10b.

TABLE 10a Efficacy of Various Mixtures of NaPT and Zinc Ions AgainstBacteria in 5% Metalworking Fluid. Zn NaPT (II) Ratio Bacteria/ml PPMPPM Zn:PT Day 1 Day 2 Day 4 Day 7 Soluble oil 0 0 — 4.0 × 10⁵ 2.0 × 10⁵ND 2.0 × 10⁴ 0 0 — 6.1 × 10⁶ ND 3.9 × 10⁶ ND 0 10 — 5.0 × 10⁵ 1.7 × 10⁵ND 2.0 × 10⁵ 0 20 — 1.4 × 10⁵ 1.6 × 10⁵ ND 2.0 × 10⁴ 0 30 — 3.0 × 10⁴7.5 × 10⁴ ND 2.0 × 10³ 0 100 — 2.0 × 10⁶ ND  0 ND 0 500 —  0 ND  0 ND 01000 —  0 ND  0 ND 0 5000 —  0 ND  0 ND 100 0 — 2.4 × 10⁵ 6.0 × 10³ ND2.0 × 10⁴ 100 0 — 5.9 × 10⁶ ND 1.5 × 10⁶ ND 100 10 1:10 1.2 × 10⁴*** 0*** ND  0*** 100 20 1:5  5.5 × 10⁴*  0*** ND  0*** 100 30  1:3.3 1.0 ×10³***  0*** ND  0*** 100 100 1:1   0*** ND  0 ND 100 500 5:1   0 ND  0ND 100 1000 10:1   0 ND  0 ND 100 5000 50:1   0 ND  0 ND 300 0 — 7.1 ×10⁴ 9.0 × 10³ ND  0 300 10 1:30 1.3 × 10⁴ 560*** ND  0 300 20 1:25 3.0 ×10³  0*** ND  0 300 30 1:10 2.9 × 10⁴ 1.4 × 10³* ND  0 500 0 — ND 450 ND 0 500 10 1:50 4.0 × 10⁵ 260* ND  0 500 20 1:25 1.1 × 10⁴ 420 ND  0 50030   1:16.7 3.2 × 10⁴ 610 ND  0 Semi-synthetic 0 0 — 1.9 × 10³ 1.2 × 10⁵ND 4.0 × 10³ 0 0 — 2.6 × 10⁶ ND 8.0 × 10⁴ ND 0 10 — 170 3.2 × 10⁵ ND 4.8× 10⁴ 0 20 — 1.5 × 10⁵ 1.4 × 10⁴ ND 4.0 × 10³ 0 30 — 1.7 × 10³ 1.5 × 10⁵ND 1.3 × 10⁵ 0 100 — 4.9 × 10⁴ ND 5.7 × 10⁴ ND 0 500 — 9.5 × 10⁴ ND 1.1× 10⁵ ND 0 1000 —  0 ND  0 ND 0 5000 —  0 ND  0 ND 100 0 — 1.8 × 10⁵ 1.9× 10⁵ ND 510 100 0 — 1.7 × 10⁴ ND 1.2 × 10⁴ ND 100 10 1:10 200  0*** ND 0*** 100 20 1:5  4.7 × 10⁴ 150*** ND  0*** 100 30  1:3.3 1.1 × 10⁴100*** ND  0*** 100 100 1:1   0*** ND  0*** ND 100 500 5:1   0*** ND 0*** ND 100 1000 10:1   0 ND  0*** ND 100 5000 50:1   0 ND  0 ND 300 0— 1.2 × 10⁵  0 ND  0 300 10 1:30 2.0 × 10⁴  0* ND  0*** 300 20 1:15 1.9× 10⁴  0 ND  0 300 30 1:10 1.6 × 10⁴  0* ND  0*** 500 0 — ND  0 ND  0500 10 1:50 ND  0* ND  0*** 500 20 1:25 2.7 × 10⁴  0 ND  0 500 30  1:16.7 1.6 × 10⁴  0* ND  0*** Synthetic 0 0 — 5.3 × 10⁶ 1.2 × 10⁵ ND1.3 × 10⁴ 0 0 — 8.4 × 10⁶ ND 3.5 × 10⁶ ND 0 10 —  30  0 ND  0 0 20 — 190 0 ND  0 0 30 —  0  0 ND  0 0 100 —  0 ND  0 ND 0 500 —  0 ND  0 ND 01000 —  0 ND  0 ND 0 5000 —  0 ND  0 ND 100 0 — 2.9 × 10⁶ 1.7 × 10⁵ ND1.5 × 10⁴ 100 0 — 2.1 × 10⁶ ND 2.0 × 10⁵ ND 100 10 1:10 2.2 × 10⁴  0 ND 0 100 20 1:5  3.0 × 10³  0 ND  0 100 30  1:3.3  0  0 ND  0 100 100 1:1  0 ND  0 ND 100 500 5:1   0 ND  0 ND 100 1000 10:1   0 ND  0 ND 100 500050:1   0 ND  0 ND 300 0 — 5.0 × 10⁴ 4.0 × 10³ ND  0 300 10 1:30  80  0ND  0 300 20 1:15 250  0 ND  0 300 30 1:10 1.8 × 10⁴  20 ND  0 500 0 —1.2 × 10⁵ 1.0 × 10³ ND  50 500 10 1:50  0  0 ND  0 500 20 1:25 810  0 ND 0 500 30   1:16.7 360  0 ND  0 ND, not determined.

TABLE 10b Efficacy of Various Mixtures of NaPT and Zinc Ions AgainstFungi in 5% Metalworking Fluid. Zn NaPT (II) Ratio Fungi/ml PPM PPMZn:PT Day 1 Day 2 Day 4 Day 7 Soluble oil 0 0 — 3.0 × 10⁴ 6.0 × 10⁴ ND4.0 × 10⁴ 0 0 — 4.1 × 10⁴ ND 3.9 × 10⁴ ND 0 10 — 3.3 × 10⁴ 4.2 × 10⁴ ND3.3 × 10⁴ 0 20 — 4.0 × 10⁴ 5.6 × 10⁴ ND 2.3 × 10⁴ 0 30 — 1.8 × 10⁴ 5.0 ×10³ ND 1.9 × 10⁴ 0 100 — 2.7 × 10⁴ ND 7.5 × 10² ND 0 500 — 3.5 × 10² ND0 ND 0 1000 — 5.5 × 10² ND 0 ND 0 5000 — 7.7 × 10² ND 0 ND 100 0 — 3.2 ×10⁴ 2.9 × 10⁴ ND 1.5 × 10⁴ 100 0 — 3.6 × 10⁴ ND 2.9 × 10⁴ ND 100 10 1:102.3 × 10⁴* 610*** ND  0*** 100 20 1:5  2.0 × 10⁴* 560*** ND  0*** 100 30 1:3.3 1.6 × 10⁴*  20*** ND  0*** 100 100 1:1  1.1 × 10⁴* ND 0*** ND 100500 5:1   0*** ND 0 ND 100 1000 10:1   0*** ND 0 ND 100 5000 50:1   0***ND 0 ND 300 0 — 1.7 × 10⁴ 1.0 × 10⁴ ND 560 300 10 1:30 2.5 × 10⁴ 1.5 ×10⁴ ND  0*** 300 20 1:15 2.4 × 10⁴ 2.0 × 10³* ND  0*** 300 30 1:10 3.5 ×10⁴ 2.0 × 10⁴ ND  0*** 500 0 — 1.9 × 10⁴ 2.8 × 10⁴ ND 610 500 10 1:502.4 × 10⁴ 1.3 × 10⁴* ND  0*** 500 20 1:25 2.9 × 10⁴ 3.5 × 10⁴ ND  0***500 30   1:16.7 1.6 × 10⁴ 1.5 × 10³ ND  0*** Semi-synthetic 0 0 — 1.0 ×10⁴ 1.4 × 10⁴ ND 4.0 × 10³ 0 0 — 2.4 × 10⁴ ND 1.4 × 10⁴ ND 0 10 — 1.0 ×10⁴ 5.0 × 10³ ND 4.8 × 10² 0 20 — 1.2 × 10⁴ 1.6 × 10⁴ ND 4.0 × 10³ 0 30— 1.2 × 10⁴ 1.5 × 10⁴ ND 1.3 × 10³ 0 100 — 3.3 × 10⁴ ND 1.1 × 10⁴ ND 0500 — 4.4 × 10⁴ ND 2.0 × 10⁴ ND 0 1000 — 4.1 × 10⁴ ND 1.0 × 10⁴ ND 05000 —  0 ND 0 ND 100 0 — 1.1 × 10⁴ 1.3 × 10³ ND  0 100 0 — 2.0 × 10⁴ ND1.0 × 10⁴ ND 100 10 1:10 200***  0*** ND  0 100 20 1:5   70***  0*** ND 0 100 30  1:3.3 150***  0*** ND  0 100 100 1:1   40*** ND 0*** ND 100500 5:1  2.2 × 10²*** ND 0*** ND 100 1000 10:1   0*** ND 0*** ND 1005000 50:1   0 ND 0 ND 300 0 — 3.0 × 10³ 570 ND  0 300 10 1:30 510*  0***ND  0 300 20 1:15 250**  0*** ND  0 300 30 1:10 630*  0*** ND  0 500 0 —9.0 × 10³ 300 ND  0 500 10 1:50 560**  0*** ND  0 500 20 1:25 290*** 0*** ND  0 500 30   1:16.7 620***  0*** ND  0 Synthetic 0 0 — 4.2 × 10⁴2.3 × 10⁴ ND 3.5 × 10⁴ 0 0 — 3.5 × 10⁴ ND 3.2 × 10⁴ ND 0 10 — 7.5 × 10⁴3.1 × 10⁴ ND 1.4 × 10⁴ 0 20 — 3.9 × 10⁴ 2.2 × 10⁴ ND 1.3 × 10⁴ 0 30 —4.2 × 10⁴ 2.1 × 10⁴ ND 5.0 × 10³ 0 100 — 2.1 × 10⁴ ND 6.0 × 10³ ND 0 500— 9.0 × 10³ ND 5.0 × 10³ ND 0 1000 — 4.0 × 10³ ND 2.0 × 10³ ND 0 5000 —2.0 × 10³ ND 4.0 × 10³ ND 100 0 — 3.0 × 10⁴ 2.0 × 10³* ND 2.0 × 10³ 1000 — 9.0 × 10³ ND 5.0 × 10³ ND 100 10 1:10 3.9 × 10⁴ 2.0 × 10³ ND 200**100 20 1:5  2.8 × 10⁴ 1.0 × 10⁴ ND 420* 100 30  1:3.3 5.0 × 10⁴ 1.0 ×10⁴ ND  0*** 100 100 1:1  7.0 × 10³* ND 0*** ND 100 500 5:1  3.0 × 10³*ND 0*** ND 100 1000 10:1  2.1 × 10²** ND 0*** ND 100 5000 50:1   0*** ND0*** ND 300 0 — 2.9 × 10⁴ 2.1 × 10⁴ ND 1.2 × 10⁴ 300 10 1:30 4.4 × 10⁴*1.7 × 10⁴* ND 130*** 300 20 1:15 3.2 × 10⁴ 1.3 × 10⁴* ND 370*** 300 301:10 7.0 × 10⁴ 1.4 × 10⁴* ND 220*** 500 0 — 2.7 × 10⁴ 4.0 × 10³ ND 3.0 ×10³ 500 10 1:50 3.5 × 10⁴* 1.3 × 10⁴ ND  30*** 500 20 1:25 5.2 × 10⁴ 1.8× 10⁴ ND  40*** 500 30   1:16.7 5.1 × 10⁴ 1.4 × 10⁴ ND  80*** ND, notdetermined

In Tables 10a and 10b, “*” indicates enhanced efficacy for mixture;e.g., efficacy of the mixture of NaPT and Zinc ions is greater than thesum of the efficacies of the corresponding NaPT and Zinc ion controls.“**” indicates enhanced efficacy for mixture; e.g., efficacy of themixture of NaPT and Zinc ions is at least 5-fold greater than the sum ofthe efficacies of the corresponding NaPT and Zinc ion controls. “***”indicates enhanced efficacy for mixture; e.g., efficacy of the mixtureof NaPT and Zinc ions is at least 10-fold greater than the sum of theefficacies of the corresponding NaPT and Zinc ion controls.

As shown in Tables 10a and 10b, initial sampling of tubes demonstratedthat all test culture tubes had at least 10⁵ bacteria/ml and 10⁴fungi/ml before treatment. The different types of metalworking fluidsvaried in the effects of treatments on the bacteria and fungalcontamination present. The microbiocidal efficacy of the controls andtreatments was defined as the difference in cells/ml between the treatedcultures and the untreated control (e.g. log₁₀ cells/ml untreated—log₁₀cells/ml treated). Enhancement of efficacy for NaPT and zinc (II) ionmixtures was indicated whenever the efficacy of the mixtures was greaterthan the sum of the efficacies of the corresponding NaPT and Zinc (II)controls. Results indicate that mixtures of pyrithione and Zinc (II)ions with weight ratios of Zinc(II)ions to pyrithione from 50:1 to 1:50demonstrated an unexpected enhancement of microbiocidal activity againstthe bacteria and the fungi in metalworking fluid at some point over theseven days of treatment.

Although the invention has been shown and described with respect toillustrative embodiments thereof, it should be appreciated that theforegoing and various other changes, omissions and additions in the formand detail thereof may be made without departing from the spirit andscope of the invention as delineated in the claims. All patents andpatent applications mentioned are herein incorporated by reference intheir entirety.

1. A coated substrate comprising: a substrate together with a coating onsaid substrate, said coating being produced by: (a) contacting saidsubstrate with a coating composition comprising pyrithione or apyrithione complex; and a zinc or copper or silver source selected fromthe group consisting of zinc or copper or silver salts, zinc or copperor silver oxides, zinc or copper or silver hydroxides, zinc or copper orsilver sulfates, zinc or copper or silver chlorides, zinc or copper orsilver metals, zinc or copper or silver complexes, and combinationsthereof; wherein the weight ratio of said zinc or copper or silversource to said pyrithione or said pyrithione complex is in the rangefrom about 1:300 to about 50:1, and wherein said antimicrobialcomposition has an enhanced biocidal effect against microorganismsselected from the group consisting of free-living microorganisms,parasitic microorganisms, adherent microorganisms, biofilms, andcombinations thereof; and (b) drying said coating composition on saidsubstrate to produce said coated substrate.
 2. The coated substrate ofclaim 1, wherein said weight ratio of said zinc or copper or silversource to said pyrithione or said pyrithione complex is in the range offrom about 1:100 to about 1:1.
 3. A coating composition, comprising: (a)a base medium comprising water or a solvent resin system selected fromthe group consisting of vinyl, alkyl, epoxy, acrylic, polyurethane andpolyester resins, and combinations thereof; and (b) a biocide comprisingan antimicrobial composition consisting essentially of pyrithione or apyrithione complex, and a zinc or copper or solver source selected fromthe group consisting of zinc or copper or silver salts, zinc or copperor silver oxides, zinc or copper or silver hydroxides, zinc or copper orsilver sulfates, zinc or copper or silver chlorides, zinc or copper orsilver metals, zinc or copper or silver complexes, and combinationsthereof; wherein the weight ratio of said zinc or copper or silversource to said pyrithione or said pyrithione complex is in the rangefrom about 1:300 to about 50:1, and wherein said antimicrobialcomposition has an enhanced biocidal effect against microorganismsselected from the group consisting of free-living microorganisms,parasitic microorganisms, adherent microorganisms, biofilms, andcombinations thereof.
 4. The coating composition of claim 3, whereinsaid weight ratio of said zinc or copper or silver source to saidpyrithione or said pyrithione complex is in the range of from about1:100 to about 10:1.
 5. A composition comprising an antimicrobialcomposition consisting essentially of pyrithione or a pyrithionecomplex; and a zinc or copper or silver source selected from the groupconsisting of zinc or copper or silver salts, zinc or copper or silveroxides, zinc or copper or silver hydroxides, zinc or copper or silversulfates, zinc or copper or silver chlorides, zinc or copper or silvermetals, zinc or copper or silver complexes, and combinations thereof;wherein the weight ratio of said zinc or copper or silver source to saidpyrithione or said pyrithione complex is in the range from about 1:300to about 50:1, and wherein said antimicrobial composition has anenhanced biocidal effect against microorganisms selected from the groupconsisting of free-living microorganisms, parasitic microorganisms,adherent microorganisms, biofilms, and combinations thereof.
 6. Thecomposition of claim 5, further comprising at least one of: a plastic, awoven fiber, a nonwoven fiber, or a combination thereof.
 7. Thecomposition of claim 5, further comprising: an adhesive base medium;wherein the composition is an adhesive composition.
 8. The compositionof claim 5, further comprising: an elastomeric base medium; wherein thecomposition is an elastomer composition.
 9. The composition of claim 5,further comprising: an adhesive base medium; wherein the composition isa sealant composition.
 10. The composition of claim 5, furthercomprising: a skin care base; wherein the composition is a skin carecomposition.
 11. A method of preserving cellulose-based material,comprising the steps of: contacting a cellulose-based material with thecomposition of claim
 5. 12. The method of claim 11, wherein saidcellulose-based material is selected from the group consisting of wood,paper, cardboard, and combinations thereof.
 13. The composition of claim5, further comprising a metal ion source.
 14. The composition of claim13, wherein the metal ion source is selected from the group consistingof titanium, cobalt, cadmium, chromium, manganese, platinum, palladium,and vanadium.
 15. The composition of claim 5, further comprising acarrier.
 16. The composition of claim 15, wherein the carrier is anaqueous media or an aqueous media in combination with at least oneorganic solvent(s).
 17. The coating composition of claim 3 wherein thebiocide is between about 0.01% and about 10% by weight based upon theweight of the base medium.